Abstract: Guizhou is a large tea-producing province, tea garden management cultivation machinery is widely used by tea farmers, and weeding is an important part in tea field management. During field experiment, it was found that winding grass on cultivating machine is a common problem during appliation. This paper conducted on the investigation on the species and length of weed in tea garden of Guizhou province, and analyze the grass winding phenomenon. Through the mechanical analysis and calculation of weed winding, the mathematical model of winding force was established. Based on the analysis of mathematical model, the measures and methods for reducing winding grass are finally concluded.

Key words: cultivation machinery, winding force, model, weed control, calculation, analysis